“Already the works our mines, impels our ships, excavates our ports and our rivers, forges iron, fashions wood, grinds grain, spins and weaves our cloths, transports the heaviest burdens, etc. It appears that it must some day serve as a universal motor, and be substituted for animal power, waterfalls, and air currents.” Which word best fits in the blank to complete the statement above? Combustion Engine , Locomotive, Steam Engine, Seed Drill